The file /usr/share/mate/applications/gtkhash.desktop has NoDisplay=true.
It's mentioned here in "apt-get changelog ubuntu-mate-default-settings":
ubuntu-mate-settings (17.10.22) artful; urgency=medium
* Hide gtkhash menu entries. * Use Green wallpaper for Slick Greeter and Live Session.
-- Martin Wimpress <email address hidden> Wed, 23 Aug 2017 17:45:40 +0100
The file /usr/share/ mate/applicatio ns/gtkhash. desktop has NoDisplay=true.
It's mentioned here in "apt-get changelog ubuntu- mate-default- settings" :
ubuntu- mate-settings (17.10.22) artful; urgency=medium
* Hide gtkhash menu entries.
* Use Green wallpaper for Slick Greeter and Live Session.
-- Martin Wimpress <email address hidden> Wed, 23 Aug 2017 17:45:40 +0100